Welding systems typically include a number of system components, such as power sources, wire feeders, travel carriages, gas and/or coolant supplies and associated controls, fume extraction equipment, etc. Beginning with the introduction of the POWER WAVE 450 inverter based arc welding supply in 1995 by The Lincoln Electric Company of Cleveland, Ohio, welding power sources have been developed where the power source inverter output waveform (or weld mode) is controlled using state table concepts to create programmable output waveforms as a series of segments or states, with transitions between states being determined according to current system conditions and a state transition table. POWER WAVE is a trademark of the assignee of the present invention. This state based control of the power source output provides a user with the ability to tailor various aspects of the welding signal applied to a specific process or application, using WAVEFORM CONTROL TECHNOLOGY, another trademark of the assignee. Various aspects of Lincoln's advanced programmable power source technology are set forth in Blankenship U.S. Pat. No. 5,278,390, which describes a system with a number of digital state tables stored in memory for controlling a welding cycle of an arc welder. The power source state tables include coded welding parameters indicating a selected function of a specific welding cycle, where a given state is performed and completed before the next state is processed, until a total welding waveform cycle is performed. The weld power source controller of Blankenship U.S. Pat. No. 5,278,390 converts the selected function of a specific digital state in the state table into welding parameters at the output of the welder operated by the weld controller. Since the POWERWAVE 450 welding power source products were introduced in the 1990's, The Lincoln Electric Company has produced a large number of welding power source products that feature state based waveform controllers. The POWER WAVE series of welding supplies, moreover, has been successfully used to generate welding power source waveforms tailored for a variety of welding process types, such as shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW, also referred to as tungsten inert gas (TIG) welding), plasma arc welding (PAW), Gas metal arc welding (GMAW, also known as metal inert gas (MIG) welding), pulsed MIG welding (GMAW-P), self-shielded flux-cored arc welding (FCAW-S), gas-shielded flux-cored arc welding (FCAW-G), submerged arc welding (SAW), variable polarity gas tungsten arc welding (VPGTAW), carbon arc gouging, pulsed TIG welding (GTAW-P), etc.
The welding waveform definitions or characteristics of the Lincoln POWER WAVE sources are stored in the form of a software “welding program”, which includes three basic components. A state table defines the logic used to produce the desired output waveform, and a data table, such as a spreadsheet, defines how the state table logic is modified or adjusted to function across a range of operation. One or more “adaptive loops” may also be employed to acquire actual information about the welding system and to make changes to the waveform to adapt for changes in the welding system in closed loop fashion. Along with the introduction of the POWER WAVE power sources, Lincoln Electric has developed and provided proprietary software known as “Weld Development” that allows a welding professional to specify a series of waveform segments or modes to program the POWER WAVE products. The Weld Development software allows a user to enter parameters and instructions into a welding waveform states to create the state table, and to specify the ranges in the data table. These state based POWER WAVE power sources and the waveforms thereof may also be customized using Lincoln Electric's WAVE DESIGNER software, where WAVE DESIGNER is also a trademark of the assignee.
Sequencers or sequence controllers monitor the status of a welding process and provide control outputs to one or more welding system components to perform a welding operation, and typically include event driven controls to adjust various aspects of a welding cycle. Early examples of welding system sequence controllers include the NA-3, NA-4, and NA-5 automatic controller products produced and marketed by Lincoln Electric since the late 1970's, featuring various adjustments to control a sequence of events such as pre-ignition, starting, welding, crater, and post-weld in a weld cycle. The NA-5 sequencer, for example, is hardware configurable to provide adjustments for: pre-ignition settings of wire feed speed (WFS) and open circuit voltage (OCV); starting segment settings of wire feed speed, voltage, and a start time; welding settings of wire feed speed, voltage, and an optional weld time; crater state settings of wire feed speed, voltage and a crater time; and post weld cycle settings for burnback time. Using this type of sequencer, a welding sequence is adjustable using a series of knobs and switches hard wired into a dedicated controller. In general, these early sequence controls implemented a generally fixed sequence of pre-defined welding system conditions with limited user adjustment of certain operating parameters (e.g., welding voltage, wire feed speed, predefined time periods, etc.) using panel mounted control adjustment knobs, where only limited changes could be made to the ordering of the system conditions, and such changes required reconfiguration of hardware wiring within the product (e.g., using jumperwires, DIP switches, etc.). More recently, improved sequence controllers have been developed, such as the POWERFEED 10 series controller offered by The Lincoln Electric Company, in which an electronic link is provided between the user controls and the associated function, where the links are typically hard coded into the machine's operating firmware or software. POWER FEED is a trademark of the assignee of the present invention. In order to modify the sequence of events or system conditions controlled by the sequencer, a firmware revision is typically required, in which control code written in C++ or other programming language must be modified, recompiled, de-bugged, and installed in the sequence controller. Thus, while such second generation sequence controller designs provide some level of improvement compared with their hardware based predecessors, the basic functionality is nevertheless predefined and difficult to modify, particularly by welding system operators. Consequently, present welding system sequence controllers do not allow easy refinement of welding processes or straightforward adaptation of a welding system to different welding operations.